The preferment method, or sponge and dough method, is a two-step process in which a sponge is made and fermented for a given period of time (pre-fermentation), followed by the addition of the rest of the ingredients to the sponge. The pre-ferment or sponge generally consists of flour, water and a leavening agent.
Traditional bread making processes rely on long pre-fermentation times with yeast and bacteria to develop the dough texture and flavor. These pre-fermentation times also provide leavening and extend the mold-free shelf-life of the dough. In these traditional methods, bacteria starter cultures may be used to standardize the process and enhance the flavor. For instance, baker's yeast typically contains some lactic acid bacteria that are responsible for a mildly sour flavor in the bread, but the type and exact quantity of these bacteria may vary.
Conversely, modern bread making processes like the sponge and dough process use a shorter fermentation (or short preferment) with yeast alone to develop the dough texture, and flavor and provide leavening. Bacteria starter cultures are not used as their lag phase is generally not compatible with the short pre-ferment time. Since baker's yeast typically contains some lactic acid bacteria, such processes lack the standardization observed in traditional bread making methods.
The preferment provides the dough development, flavor and leavening. Yeast metabolizes the flour nutrients and produces yeast flavors (alcohol and esters for example) as well as CO2. CO2 dissolves in the dough in the form of carbonic acid (H2CO3) which in turn drives the dough pH from about 6.5-6 to about 5, the pH at which no more CO2 is dissolved in the dough. The excess CO2 is further de-gassed from the dough. Such a pH contributes to activating anti-molding organic acid-based preservatives (such as propionic, acetic and fumaric acids).
Consequently, breads or bread-like products produced using modern processes are more alcoholic and do not exhibit the characteristic flavor of traditional breads or bread-like products in which the long pre-fermentation time with yeast and bacteria results in a more complex and less alcoholic flavor.
Bacteria starter cultures are not used in the sponge since their lag phase is not compatible with the short preferment time. Lactic acid-producing bacteria (LAB) are, however, used along with wild yeasts in traditional methods with long pre-fermentation times for the production of sourdough. Sourdough breads and break-like products exhibit a mildly sour flavor due to the lactic acid and other organic acids produced and are characterized by an open and airy crumb texture.
Accordingly, there remains a need for improved modern processes of manufacturing a dough mixture that allow for the production of leavened products such as, for example, bread or bread-like products exhibiting a more complex flavor than modern processes currently used in the art with a dough quality, texture and leavening comparable to traditional processes.